Cancer has become one of main diseases which are increasingly common and severely threaten human lives and life quality. As aged population continuously increases, it is predicted that the occurrence of cancer will continue to increase. At present, there are mainly three kinds of methods for treating cancer, including surgery, radiation therapy, and chemotherapy. The selection of therapeutic means of cancer depends on the type, the site, and the spreading of cancer. Chemotherapy is a therapeutic means, which uses chemical drugs to kill tumor cells. It is a systemic therapeutic means, and has therapeutic effect on all of primary lesions, metastatic lesions, and subclinical metastatic lesions. As for cancers, which will not be subjected to surgery and radiation therapy, only chemotherapy can be relied on. At present, clinically commonly-used chemotherapeutic anti-cancer drugs have severe side effects due to lack of targeting. These side effects usually limit applications of chemotherapeutic drugs and results in loss of therapeutic options for many cancers. For example, severe side effects, which are caused by non-specific toxicities from most of anthracycline antineoplastic drug molecules and platinum-containing substances, greatly limit the use of these chemotherapeutic drugs. Therefore, the development of a drug carrier, which is capable of specifically targeting tumor tissues and reducing toxic and side effects, is a challenge urgent to be solved in the field of cancer therapy.